[FIX] 채팅 api 에러 수정

src/main/java/com/assu/server/domain/chat/controller/ChatController.java

@@ -2,8 +2,11 @@
 
 import com.assu.server.domain.chat.dto.ChatRequestDTO;
 import com.assu.server.domain.chat.dto.ChatResponseDTO;
+import com.assu.server.domain.chat.dto.ChatRoomUpdateDTO;
+import com.assu.server.domain.chat.repository.MessageRepository;
 import com.assu.server.domain.chat.service.ChatService;
 import com.assu.server.global.apiPayload.code.status.SuccessStatus;
+import com.assu.server.global.util.PresenceTracker;
 import com.assu.server.global.util.PrincipalDetails;
 import io.swagger.v3.oas.annotations.Operation;
 import lombok.RequiredArgsConstructor;
@@ -24,6 +27,8 @@
 public class ChatController {
     private final ChatService chatService;
     private final SimpMessagingTemplate simpMessagingTemplate;
+    private final PresenceTracker presenceTracker;
+    private final MessageRepository messageRepository;
 
     @Operation(
             summary = "채팅방을 생성하는 API",
@@ -61,10 +66,33 @@ public BaseResponse<List<com.assu.server.domain.chat.dto.ChatRoomListResultDTO>>
     )
     @MessageMapping("/send")
     public void handleMessage(@Payload ChatRequestDTO.ChatMessageRequestDTO request) {
-        log.info("[WS] handleMessage IN: {}", request);   // ★ 호출 여부 확인
-        ChatResponseDTO.SendMessageResponseDTO response = chatService.handleMessage(request);
-        log.info("[WS] handleMessage SAVED id={}", response.messageId()); // 저장 확인용
-        simpMessagingTemplate.convertAndSend("/sub/chat/" + request.roomId(), response);
+        // 먼저 접속 여부 확인 후 unreadCount 계산
+        boolean receiverInRoom = presenceTracker.isInRoom(request.getReceiverId(), request.getRoomId());
+        int unreadForSender = receiverInRoom ? 0 : 1;
+        request.setUnreadCountForSender(unreadForSender);
+
+        ChatResponseDTO.SendMessageResponseDTO saved = chatService.handleMessage(request);
+        simpMessagingTemplate.convertAndSend("/sub/chat/" + request.getRoomId(), saved);
+
+        if (!receiverInRoom) {
+            Long totalUnreadCount = messageRepository.countUnreadMessagesByRoomAndReceiver(
+                    request.getRoomId(),
+                    request.getReceiverId()
+            );
+
+            ChatRoomUpdateDTO updateDTO = ChatRoomUpdateDTO.builder()
+                    .roomId(request.getRoomId())
+                    .lastMessage(saved.message())
+                    .lastMessageTime(saved.sentAt())
+                    .unreadCount(totalUnreadCount)
+                    .build();
+
+            simpMessagingTemplate.convertAndSendToUser(
+                    request.getReceiverId().toString(),
+                    "/queue/updates",
+                    updateDTO
+            );
+        }
     }
 
     @Operation(

src/main/java/com/assu/server/domain/chat/converter/ChatConverter.java

@@ -57,7 +57,8 @@ public static Message toMessageEntity(ChatRequestDTO.ChatMessageRequestDTO reque
                 .chattingRoom(room)
                 .sender(sender)
                 .receiver(receiver)
-                .message(request.message())
+                .message(request.getMessage())
+                .unreadCount(request.getUnreadCountForSender())
                 .build();
     }
 
@@ -70,6 +71,7 @@ public static ChatResponseDTO.SendMessageResponseDTO toSendMessageDTO(Message me
                 .message(message.getMessage())
                 .sentAt(message.getCreatedAt())
                 .messageType(message.getType())
+                .unreadCountForSender(message.getUnreadCount())
                 .build();
     }
 

src/main/java/com/assu/server/domain/chat/dto/ChatMessageDTO.java

@@ -22,6 +22,9 @@ public class ChatMessageDTO {
     private String message;
     private LocalDateTime sendTime;
 
+    @JsonProperty("unreadCountForSender")
+    private Integer unreadCount;
+
     @JsonProperty("isRead")
     private boolean isRead;
 

src/main/java/com/assu/server/domain/chat/dto/ChatRequestDTO.java

@@ -1,6 +1,7 @@
 package com.assu.server.domain.chat.dto;
 
 import lombok.Getter;
+import lombok.Setter;
 
 public class ChatRequestDTO {
     @Getter
@@ -9,10 +10,13 @@ public static class CreateChatRoomRequestDTO {
         private Long partnerId;
     }
 
-    public record ChatMessageRequestDTO(
-        Long roomId,
-        Long senderId,
-        Long receiverId,
-        String message
-        ) {}
+    @Getter
+    @Setter
+    public static class ChatMessageRequestDTO {
+        private Long roomId;
+        private Long senderId;
+        private Long receiverId;
+        private String message;
+        private int unreadCountForSender;
+    }
 }

src/main/java/com/assu/server/domain/chat/dto/ChatResponseDTO.java

@@ -33,8 +33,15 @@ public record SendMessageResponseDTO(
         String message,
         MessageType messageType,
         @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
-        LocalDateTime sentAt
-    ) {}
+        LocalDateTime sentAt,
+        Integer unreadCountForSender
+    ) {
+        public SendMessageResponseDTO withUnreadCountForSender(Integer count) {
+            return new SendMessageResponseDTO(
+                    messageId, roomId, senderId, receiverId, message, messageType, sentAt, count
+            );
+        }
+    }
 
     // 메시지 읽음 처리
     public record ReadMessageResponseDTO(

src/main/java/com/assu/server/domain/chat/dto/ChatRoomUpdateDTO.java

@@ -0,0 +1,15 @@
+package com.assu.server.domain.chat.dto;
+
+import lombok.Builder;
+import lombok.Getter;
+
+import java.time.LocalDateTime;
+
+@Getter
+@Builder
+public class ChatRoomUpdateDTO {
+    private Long roomId;
+    private String lastMessage;
+    private LocalDateTime lastMessageTime;
+    private Long unreadCount; // 해당 채팅방의 총 안읽은 메시지 수
+}

src/main/java/com/assu/server/domain/chat/entity/Message.java

@@ -36,6 +36,8 @@ public class Message extends BaseEntity {
 
 	private String message;
 
+    private Integer unreadCount;
+
 //	private LocalDateTime sendTime;
 //	private LocalDateTime readTime;
 
@@ -47,5 +49,6 @@ public class Message extends BaseEntity {
 
     public void markAsRead() {
         this.isRead = true;
+        this.unreadCount = 0;
     }
 }

src/main/java/com/assu/server/domain/chat/repository/MessageRepository.java

@@ -7,7 +7,6 @@
 import org.springframework.data.repository.query.Param;
 
 import java.util.List;
-import java.util.Optional;
 
 public interface MessageRepository extends JpaRepository<Message, Long> {
     @Query("""
@@ -18,13 +17,23 @@ public interface MessageRepository extends JpaRepository<Message, Long> {
 """)
     List<Message> findUnreadMessagesByRoomAndReceiver(Long roomId, Long receiverId);
 
+    @Query("""
+        SELECT COUNT(m)
+        FROM Message m
+        WHERE m.chattingRoom.id = :roomId
+        AND m.receiver.id = :receiverId
+        AND m.isRead = false
+    """)
+    Long countUnreadMessagesByRoomAndReceiver(@Param("roomId") Long roomId, @Param("receiverId") Long receiverId);
+
 
     @Query("""
         SELECT new com.assu.server.domain.chat.dto.ChatMessageDTO (
             m.chattingRoom.id,
             m.id,
             m.message,
             m.createdAt,
+            m.unreadCount,
             m.isRead,
             CASE WHEN m.sender.id = :memberId THEN true
             ELSE false

src/main/java/com/assu/server/domain/chat/service/ChatServiceImpl.java

@@ -83,22 +83,18 @@ public ChatResponseDTO.CreateChatRoomResponseDTO createChatRoom(ChatRequestDTO.C
     @Transactional
     public ChatResponseDTO.SendMessageResponseDTO handleMessage(ChatRequestDTO.ChatMessageRequestDTO request) {
         // 유효성 검사
-        ChattingRoom room = chatRepository.findById(request.roomId())
+        ChattingRoom room = chatRepository.findById(request.getRoomId())
                 .orElseThrow(() -> new DatabaseException(ErrorStatus.NO_SUCH_ROOM));
-        Member sender = memberRepository.findById(request.senderId())
+        Member sender = memberRepository.findById(request.getSenderId())
                 .orElseThrow(() -> new DatabaseException(ErrorStatus.NO_SUCH_MEMBER));
-        Member receiver = memberRepository.findById(request.receiverId())
+        Member receiver = memberRepository.findById(request.getReceiverId())
                 .orElseThrow(() -> new DatabaseException(ErrorStatus.NO_SUCH_MEMBER));
 
         Message message = ChatConverter.toMessageEntity(request, room, sender, receiver);
-//        messageRepository.save(message);
-        log.info("saved message start");
         Message saved = messageRepository.saveAndFlush(message);
-        log.info("saved message middle");
         log.info("saved message id={}, roomId={}, senderId={}, receiverId={}",
                 saved.getId(), room.getId(), sender.getId(), receiver.getId());
 
-        log.info("saved message end");
         boolean exists = messageRepository.existsById(saved.getId());
         log.info("Saved? {}", exists); // true 아니면 트랜잭션/DB 문제
         return ChatConverter.toSendMessageDTO(saved);

src/main/java/com/assu/server/global/util/PresenceTracker.java

@@ -0,0 +1,90 @@
+package com.assu.server.global.util;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.context.event.EventListener;
+import org.springframework.messaging.simp.stomp.StompHeaderAccessor;
+import org.springframework.stereotype.Component;
+import org.springframework.web.socket.messaging.SessionDisconnectEvent;
+import org.springframework.web.socket.messaging.SessionSubscribeEvent;
+import org.springframework.web.socket.messaging.SessionUnsubscribeEvent;
+
+import java.security.Principal;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+@Component
+@Slf4j
+public class PresenceTracker {
+    private final Map<Long, Set<Long>> roomSubscribers = new ConcurrentHashMap<>();
+    private final Map<String, Long> sessionToMember = new ConcurrentHashMap<>();
+    private final Map<String, Set<Long>> sessionToRooms = new ConcurrentHashMap<>();
+
+    private Long parseRoomId(String dest) { // "/sub/chat/26" -> 26
+        if (dest == null) return null;
+        String[] p = dest.split("/");
+        if (p.length >= 4 && "chat".equals(p[2])) return Long.valueOf(p[3]);
+        return null;
+    }
+
+    private Long memberIdFrom(Principal user) {
+        if (user == null) return null;
+        // StompAuthChannelInterceptor 에서 Principal.name을 memberId로 넣어두었다고 가정
+        return Long.valueOf(user.getName());
+    }
+
+    @EventListener
+    public void onSubscribe(SessionSubscribeEvent e) {
+        var acc = StompHeaderAccessor.wrap(e.getMessage());
+        Long roomId = parseRoomId(acc.getDestination());
+        Long memberId = memberIdFrom(e.getUser());
+        if (roomId == null || memberId == null) return;
+
+        String sessionId = acc.getSessionId();
+        sessionToMember.put(sessionId, memberId);
+        sessionToRooms.computeIfAbsent(sessionId, k -> ConcurrentHashMap.newKeySet()).add(roomId);
+        roomSubscribers.computeIfAbsent(roomId, k -> ConcurrentHashMap.newKeySet()).add(memberId);
+
+        log.debug("SUB: member {} -> room {}", memberId, roomId);
+    }
+
+    @EventListener
+    public void onUnsubscribe(SessionUnsubscribeEvent e) {
+        var acc = StompHeaderAccessor.wrap(e.getMessage());
+        String sessionId = acc.getSessionId();
+        var rooms = sessionToRooms.getOrDefault(sessionId, Set.of());
+        Long memberId = sessionToMember.get(sessionId);
+        if (memberId != null) {
+            for (Long roomId : rooms) {
+                var set = roomSubscribers.get(roomId);
+                if (set != null) {
+                    set.remove(memberId);
+                    if (set.isEmpty()) roomSubscribers.remove(roomId);
+                }
+            }
+        }
+        sessionToRooms.remove(sessionId);
+        log.debug("UNSUB: session {}", sessionId);
+    }
+
+    @EventListener
+    public void onDisconnect(SessionDisconnectEvent e) {
+        String sessionId = e.getSessionId();
+        Long memberId = sessionToMember.remove(sessionId);
+        var rooms = sessionToRooms.remove(sessionId);
+        if (memberId != null && rooms != null) {
+            for (Long roomId : rooms) {
+                var set = roomSubscribers.get(roomId);
+                if (set != null) {
+                    set.remove(memberId);
+                    if (set.isEmpty()) roomSubscribers.remove(roomId);
+                }
+            }
+        }
+        log.debug("DISCONNECT: session {}", sessionId);
+    }
+
+    public boolean isInRoom(Long memberId, Long roomId) {
+        return roomSubscribers.getOrDefault(roomId, Set.of()).contains(memberId);
+    }
+}